Vatican Greek manuscript No. 840 aroused a certain interest of researchers.
A more detailed description of the manuscript was given by the Russian Byzantine scientist Vladimir Nikolayevich Beneshevich (1914).
The last, 243th sheet of the manuscript was included in the number of additional sheets accidentally. It contains records relating to the Russian Church [Beneshevich, Pp. 167 – 169]. The article by M. Priselkov and M. Vasmer had been devoted to it [Priselkov M. D., Vasmer M. G. on the history of the Russian church of the 14th century. – Notes of the department the Russian language and literature of the Academy of Sciences, 1916, Vol. 21, book. 1, p. 48 to 70].
Later attention was paid to the code 840 by Peter Schreiner (1975).
A separate article on the code 840 was written by B. L. Fonkich (2003).
The biggest problem that can not be solved without examining the manuscript – is the question of the dating of the sheet of "Excerpts". As already noted, anybody did not study manuscript filigrees.